After getting the "Nissan is working on a fix, just wait" response for a while, my service dept. just informed me that I will now be getting a new and improved "upgraded" tranny which will solve my problem, and the rattle will not return. So either the new tranny's are undergoing better quality control, or they actually recieved an upgraded design - either way I'm happy for the time being. We'll see how it runs after major surgery, it should run exactly how it did when new, and I'm sure the rattle will not return.